Pet door assemblies are well known. They usually include a frame mounted in an existing closure and a closure member or flap that can be urged open by the pet. The closure member is mounted on the frame to be displaced, either by gravity or a spring, back into a closed position, once the pet has passed through an opening defined by the frame.
In U.S. Pat. No. 3,985,174, published Oct. 12, 1976, there is described a pet door that is installed in a window screen or screen door. In this patent, the frame of the pet door is fastened to a facing surface of a frame of the window screen or screen door. A problem with this arrangement is that the frame has to suit the dimensions of the window screen or screen door. In particular, a distance from the screen itself to the associated facing surface is critical. Furthermore, in the case of a sliding screen door, the frame could interfere with relatively sliding door members.
In U.S. Pat. No. 4,334,573, published Jun. 15, 1982, there is described a pet access door kit. This kit is essentially a frame that is fastened to a facing surface of the frame of a screen door. Screen material bounded by the frame is cut and a weight is fastened to the screen material so that the screen material defines a flap. This arrangement also has the problems of interference and limited adjustability described above.
In U.S. Pat. No. 5,701,813, published Dec. 30, 1997, there is described a pet door also for a screen door. As with the previous patents, this patent displays the same problems with a frame or mounting bracket being fastened to a facing surface of a frame of the screen door.
In some cases, for example in U.S. Pat. No. 5,535,804 published Jul. 16, 1996, the frame of the pet door is mounted directly on to the screen, without engagement with a frame of the window or screen door. Applicant submits that such an arrangement will not be able to withstand the rigors of day-to-day use, especially with energetic, larger dogs.
The Applicant is the proprietor of Australian patent no. 759436, the contents of which are hereby specifically incorporated by reference. This patent covers a pet door that is mountable in a security screen door commonly found in Australia. However, Applicant has found that such security screen doors are not generally found in the United States. Rather, a simple frame and screen arrangement appears to be predominant in the United States, particularly in the warmer areas. Applicant has developed the pet door of this Australian patent further in conceiving the present invention, so that the pet door can be used with conventional screen doors.